1. Field of the Invention
This invention relates to a shock-absorbing suspension device for a wheeled vehicle, more particularly to a shock-absorbing suspension device for coupling a frame of a wheeled vehicle to a wheel axle.
2. Description of the Related Art
In co-pending U.S. patent application Ser. Nos. 12/038,865 and 12/039,142, the applicant disclosed a shock-absorbing suspension device for coupling a frame of a wheeled vehicle to a wheel axle so as to minimize impact of shock generated one the frame as a result of movement of the wheeled vehicle over an uneven road surface. The shock-absorbing suspension device generally includes a mounting rod adapted to be mounted on the frame, a wheel rod adapted to be mounted on the wheel axle, and a linkage mechanism which is disposed to couple the mounting rod to the wheel rod and which can sway in response to jerking movement of the wheel rod so as to dampen the shock transmitted to the mounting rod.
A steering column is mounted on the mounting rod, so that the mounting rod is swivelable to turn the wheel rod so as to control the advancing direction of the vehicle. Since the entire linkage mechanism has to be turned together with the mounting rod during a steering operation, a relatively large force needs to be applied to the mounting rod.